It's possible to collect Social Security while you are still employed. You can collect both Social Security retirement and survivorship benefits (though not at the same time) even if you are currently employed.
The Benefits of Working While Collecting Social Security
Each year, the Social Security Administration (SSA) reviews the earnings of all Social Security recipients. If your the income is higher in the years you are working and receiving Social Security benefits, your future benefit amount may increase because it is based on the average income you made during all of your working years. This increase is paid out retroactively to the January after the income was earned.
Additionally, if you continue to work while receiving survivor benefits, the additional earnings you make could lead to your own Social Security benefits being higher than your current survivor benefits, which would increase your retirement income. (For related reading, see "How Social Security Survivor Benefits Work.")
Income Limits and Social Security Benefits
If you have not reached full retirement age and earn more than the yearly limit, your benefit amount may be reduced. If you are under the full retirement age for the entire year, the SSA deducts $1 for every $2 you earn over the yearly limit. The 2018 income limit is $17,040.
If you reach full retirement age within the year, the SSA deducts $1 for every $3 you earn over the yearly limit. The 2018 limit for this is $45,360. This only includes income you earned in the months prior to reaching retirement age.
When you reach full retirement age, your earnings no longer negatively impact your Social Security benefits, regardless of how much you earn. When the SSA recalculates your Social Security benefit amount, any months when your benefits were reduced or withheld are not included in the calculations.
(For related reading, see "Why Working After Retirement Is Good for Your Health.")